Many reasons exist for dispensing liquid adhesives, such as hot melt adhesives, in the form of a thin filament or strand with a controlled pattern. Conventional patterns used in the past have been patterns involving a swirling effect of the filament by impacting the filament with a plurality of jets of air. This is generally known as controlled fiberization or CF in the hot melt adhesive dispensing industry. Controlled fiberization techniques are especially useful for accurately covering a wider region of a substrate with adhesive dispensed as single filaments or as multiple side-by-side filaments from nozzle passages having small diameters, such as on the order of 0.010 inch to 0.060 inch. The width of the adhesive pattern placed on the substrate can be widened to many times the width of the adhesive filament itself. Moreover, controlled fiberization techniques are used to provide better control of the adhesive placement. This is especially useful at the edges of a substrate and on very narrow substrates, for example, such as on strands of material, such as Lycra®, used in the leg bands of diapers. Other adhesive filament dispensing techniques and apparatus have been used for producing an oscillating pattern of adhesive on a substrate or, in other words, a stitching pattern in which the adhesive moves back-and-forth generally in a zig-zag form on the substrate. Some types of these dispensers or applicators have a series of liquid and air orifices arranged on the same plane.
Various types of nozzles or die tips, such as those of the type described above, have been used to dispense adhesive filaments onto one or more elastic strands. For such applications, the strand or strands typically need to be guided at specific spaced apart positions as the adhesive is discharged onto the strand or strands. Even a single strand needs to be guided and stabilized to ensure accurate placement of the adhesive on the strand. For this purpose, strand guides may take the form of rollers which are fixed to the dispensing module or some other fixed structure. While this works appropriately in many situations, the strand guides do present additional expense and spacing considerations. Also, the strand guides may cause airborne contaminants, such as dust or fiber, to accumulate on the strand at the interface between the guide and the strand. Accumulated debris of this type can then collect into a mass with the adhesive and become smeared or otherwise deposited onto a substrate being joined with the strand. This can reduce the quality of the resulting product.
It would therefore be desirable to provide a nozzle guide which reduces or eliminates the problems noted above while, at the same time, achieving further advantages and advancements over the existing technology.